16 Aug
2005
16 Aug
'05
3:51 p.m.
That reminds me or another little machine from Motorola. They
called it the Educator II (and was the first computer I ever
owned). Their cassette interface worked pretty much the same
way. They toggled a pin on the PIA in software for a simple
FM encoding at 110 baud. Even the receive side was software.
Many microcomputer cassette interfaces are bit-banged. It works quite
well for that application, because you know when data could be coming
from the cassette (the user has executed a LOAD command
or whatever it's
called), so you can put the microprocesosr into a loop looking
for
transitions on the input pin.
It works less well for linking to a terminal, because you have know idea
when the user is going to press a key :-)
-tony